How bad did tires affect milage on an Ecoboost

live2rideyamaha · Jan 25, 2013

So I have been a diesel guy for about 8 years and just got sick of the maintenance costs and fuel for pulling a sled trailer twice a year maybe so I bit the bullet and bought a 2012 150 eco I absolutly love the truck tons of power and it does everything i will ever need but at 1000 miles I could not handle the Pirellis any more so I put a 3inch leveling kit on it with 295/65/20s i still only have right at 4000 miles but ever since i put the tires on i get like 11-12 MPg in town and maybe 14-15 on the highway. If I new the tires were going to affect the mileage that bad I would of done it anyway haha but is anyone else having this same issue?
thanks

fat · Jan 25, 2013

I found the same thing. Mileage dropped to about 13.5 mixed driving.

freeflorider · Jan 25, 2013

Getting mpg

How much did you loose on the mileage over stock? Perhaps with a bigger rim/tire combo it's messing with the on board computer, it happens but I'm sure there is a tuner out there that can calibrate your tire size and bring back the mpg's

TurboM700 · Jan 25, 2013

Did you figure in the oversize tires when you did the HAND calcs?

This can change MPG to more positive.

Mike

pfi572 · Jan 25, 2013

Gas or Diesel tires effect fuel mileage .
Bigger tires are heavier,most times wider, more aggressive and so on.
Lifting truck has for wind resistance also.
Had a stock truck with 88000 Kms that received 21 to 22 miles per gallon stock.
Put 35 inch tires , 6 inch lift , banks programmer, intercooler, exhaust and intake.
Same truck and 17 miles per gallon right after install.
Small tires and keep it low to the ground for mileage.

live2rideyamaha · Jan 25, 2013

here it is before and after. when the truck was new i was getting around 19 on the highway and about 15 in town with the stock tires. i knew that the tires would make a difference just didnt know it would be that big either way I love the truck and plan on having it for a long itme just was wondering if any one was hacing the same deal. I did hear from someone and this could be total bull but my salesman told me that the truck learns how to shift from how you drive the first couple weeks. I was wondering if this is true and does it continue to learn or is there something in the computer that might need to be reset sounds dumb but hey its worth a shot

volcano buster · Jan 25, 2013

They do have adaptive learning in the computer to keep track of how you drive. I bought a '12 SuperCrew with the 5.0 and when I first got it the thing would downshift and rev the engine all the time. Now, it tends to lug the motor a little better when adding a bit more fuel before it decides to shift down. I am watching the fuel all the time so I am trying not to mash it all the time so it thinks I'm an old man, until the size 16 hits the floor occasionally.

Can't say the mileage went up due to the adaptive learning, but it likely easier on my drive train by not shock loading it was 4000 rpm drops all the time.

freeflorider · Jan 25, 2013

Yes I believe there is truth to that. I have also hear if you want to reset the computer you just unhook your battery's and leave it sit for a while and then hook em back up...if I remember right your tranny will shift diffrent and you'll feel a change in the truck.
Truck looks better with the bigger tires anyhow.

snokaw · Jan 27, 2013

I came from the Super Duty Diesels also. I like my F150 Eco, swapped tires the day I bought it, 285/70/17 BFG, 3.73 gears. 14-15 MPG mixed and about 15-17 highway. Towing drops it to about 9.5-12 mpg depending on wind and speed.

It's a truck, I want truck tires that perform.

The Wife doing a snow dance today for our trip to Montana on Friday...

XXL · Jan 28, 2013

She aint doin a very good job, we got nothin here!!! But thanks for tryin!!

BLITZKRIEG · Jan 28, 2013

Ford already found the problem, they even put a
circle around it on the grill!
BWahahaha:face-icon-small-ton

Chadx · Jan 28, 2013

How did you account for your odometer showing way less miles than you actually traveled with the taller tires now in place? If that isn't accounted for, your computer mileage will be way off as will your hand calculated mileage.

For example, if you were traveling 100 miles before and using 7 gallons, you were getting 14.3 mpg. If you put on the bigger tires, besides the decrease in mileage due to weight, rolling resistance, worse aerodynamics of your truck (higher off the ground), etc. that you already know about, if you didn't recalibrate your odometer, and your tires are say 15% taller, your odometer would show 10% fewer miles than traveled. So besides the worse mileage, you are also just calculating 15% fewer miles traveled hence cheating yourself out of calculating your true mileage. 15% of 17mpg is 2.55mpg change in calculated mpg due only to the inaccurate odometer.

I don't know what your stock tires size was, but, for example, going from a 265/65-17 to a 295/65-20 is a 14.8% increase (4.5" taller) so your mileage will calculate a about 15% less PLUS your actual MPG lose on top of that.

w4cstriker · Jan 28, 2013

Went from a duramax to this eco first new ford. I put a level kit first day and 275/60/r20 accorinding to a tire cal online im a 1 mpg off my mpg.Love the truck mpg is close to my 2011 duramax just.60 to .80 cents less a gallon.

Coldfinger · Jan 28, 2013

Waht is your stock tire size and please list your new size again then I can figure your % change in tire speed.

w4cstriker · Jan 29, 2013

my tire was stock 275/55 r20 I figure 2 to 3 mph off

Chadx · Jan 29, 2013

275/55-20 to 295/65-20 is a 10% difference (diameter is 3.19" taller and circumference is 10" more).

So at an indicated 65 mph you are now going 71.5 (provided your speedometer was accurate to begin with which most aren't).

Revolutions per mile was 632 and is now only 574. 632.04

When calculating your mileage, you'll want to account for your odometer indicating 10% low (and realize that your odometer will be 10% low when you are due for maintenance and go to re-sell).

w4cstriker · Jan 29, 2013

275/55r20 vs 275/60r20 is that much difference?

Goinboardin · Jan 29, 2013

Can't the ECM be reprogrammed for a larger tire? I don't drive a newer truck, but even on my 96' F150 I'm nearly certain they can be calibrated/reprogrammed for different tire diameter.

volcano buster · Jan 29, 2013

Les Schwab can do it when you buy the tires, or at least they used to be able to.

Coldfinger · Jan 29, 2013

w4cstriker said:
275/55r20 vs 275/60r20 is that much difference?

The calculators I used say 3.4% diff in speedo.
With larger tires you are going 67.21 when your speedo reads 65.

65 mph (104.61 km/h)

67.21 mph (108.16 km/h)

http://www.tacomaworld.com/forum/tirecalc.php
or
http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp

275 = 275mm width
55 = sidewall height % of width
20 = rim diameter in inches

How bad did tires affect milage on an Ecoboost

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